Metal salts of citramic acids



United States Patent 3,262,955 METAL SALTS 0F CITRAMIC ACIDS Paul Y. C.Gee, Woodbury, and Harry J. Andress, Jr., Pitman, N.J., assignors toSocony Mobil Oil Company, Inc., a corporation of New York No Drawing.Original application June 1, 1962, Ser. No. 199,280, now Patent No.3,192,160, dated June 29, 1965. Divided and this application Nov. 12,1964, Ser. No. 410,718

5 Claims. (Cl. 260-4299) This application is a division of ourapplication Serial Number 199,280, filed June 1, 1962, now Patent No.3,192,160, and relates to the improvement of liquid petroleum fractionsand, more particularly, to mineral oil compositions adapted for use asfuel oils containing certain additives adapted to inhibit the appearanceof sediment during prolonged storage periods, to preventscreen-clogging, and to prevent rusting of ferrous metal surfaces, andto mineral oil compositions adapted for use as lubricating oilscontaining such additives as rust'inhibitors and which, while impartingsuch desired properties to fuel oils and lubricating oils, also inhibitssuch fuel oils and lubricating oils against objectionableemulsification.

It is well known that fuel oils are prone to form sludge or sedimentduring periods of prolonged storage. This sediment, of course, has anadverse effect on burner opera- ,tion because it has a tendency to clogscreens and nozzles.

In addition to sediment formed during storage, most fuel oils containother impurities, such as rust, dirt, and entrained water. The sedimentand impurities tend to settle out on equipment parts, such as nozzles,screens, filters, etc., thereby clogging them and causing the equipmentto fail. A further factor, incident to the storage and handling of fueloils, is the breathing of storage vessels. This results in theaccumulation of considerable amounts of water in the tanks, whichpresents a problem of rusting in the tanks. Then, when the oil isremoved for transportation sufficient water may be carried along tocause rusting of ferrous metal surfaces in pipelines, tankers and thelike.

Generally, it has been the practice to overcome the aforedescribeddifficulties with fuel oils with a separate additive for each purpose,i.e., with a sediment inhibitor, an anti-screen clogging agent, and anantirust agent. The use of several additives, however, gives rise toproblems of additive compatibility, thus restricting the choice ofadditive combinations. In addition, the use of a plurality of additivesunduly increases the cost of the fuel.

As is also well known to those skilled in the art, the rusting offerrous metal surfaces has been a common occurrence in the field oflubrication and, particularly, in steam turbine lubrication during theinitial operation of new installations. Rusting is most pronounced atpoints where the clearance between bearing surfaces is very small, as ingovernor mechanism, and is usually caused by water entering the oilsupply, as by condensation and entrainment in the oil throughout thecirculating system, thereby coming into contact with the ferrous metalsurfaces. As in the case of fuel oils, emulsification of the oil is alsoobjectionable in lubricating oils and, in the case of turbinelubricating oils, is particularly objectionable in that the desireddegree of lubrication is reduced for metal parts in contact withemulsified oil.

It has now been found that all such problems en countered with mineraloil compositions, such as fuel oils and lubricating oils, are obviatedby the use of a single fuel oil addition agent in the form of certainmetal salts of partial amides of citric acid.

In general, the present invention relates to mineral oil compositionscontaining a small amount, suflicient to provide the aforesaidimprovements, of a compound selected ice from the group consisting of(a) metal salts of the following formulas (A):

CHtCONHR CHr-C 0-M-oR' and mixtures thereof, wherein M is a divalentmetal, and R is an alkyl group of from about 4 to about 30 andpreferably about 12 to 24 carbon atoms and having a tertiary carbon atomattached to the nitrogen atom, and R is alkyl. In

such salts, the metal component M is, preferably, a metal from the groupconsisting of magnesium, barium, calcium and zinc but, if desired, themetal M can be another metal (e.g., strontium) from group II of thePeriodic Table. The alkyl group R is, preferably, a lower molecularweight alkyl group and, for example, containing from about 1 to about 18carbon atoms and, more preferable, a methyl group.

The citramic acids that can be used for preparation of such metal saltscan be made by any of the methods known in the art for preparing suchcompounds and, for example, by heating two moles of an appropriatealiphatic primary amine with one mole of citric acid monohydrate at1.50-165 C. for from 2 to 6 hours with elimination of three moles ofwater to form the diamide of citric acid; and by heating, at 145 C. forabout three hours, one mole of the appropriate aliphatic primary aminewith one mole of citric acid monohydrate to form the monoamide of citricacid.

The amines utilizable in forming the citramic acids are thetertiary-alkyl primary mono-amines in which a primary amino group (--NHis attached to a tertiary carbon atom of an alkyl group of between 4 and30 carbon atoms. Thus, the amines contain the group:

and of which non-limiting examples include t-dodecyl primary amine,t-tetradecyl primary amine, t-pentadecyl primary amine, t-hexadecylprimary amine, t-octadecyl primary amine, t-eicosyl primary amine,t-tetracosyl primary amine, and t-triacontyl primary amine. Mixtures ofsuch amines can also be used. The use of amines containing such atertiary carbon atom group, whereby the group R in the foregoingformulas is an alkyl group having a tertiary carbon atom attached to thenitrogen atom of the metal salts of the citramic acid, is of substantialimportance as it provides such metal salts of citramic acid thatsubstantially inhibit emulsification of mineral fuel oils andlubricating oils.

The aforesaid metal salts of such citramic acids can be prepared byheating the citramic acids with the appropriate group II metalalkoxides, or metal hydroxides or, if desired, by use of an alkali metalhydroxide and double displacement with, for example, a group II metalhalide (e.g., zinc chloride). Thus, for preparation of a normal metalsalt (i.e., aforesaid formulas A), one mole of the desired group IImetal compound (e.g., alkoxide, hydroxide) is heated with two moles ofthe citramic acid; for preparation of the alkoxy metal salts (i.e.,formula B), one mole of the citramic acid is heated with one mole of thedesired group II metal alkoxide; for preparation of the metal salts offormulas (C), one mole of the metal alkoxide or metal hydroxide with twomoles of the mono amide of citric acid; and for formulas (D), two molesof the metal alkoxides or hydroxides with one mole of monoamide ofcitric acid.

The fuel oils that are improved in accordance with this invention arehydrocarbon fractions having an initial boiling point of at least about100 F. and an end boiling point no higher than about 750 F., and boilingsubstantially continuously throughout their distillation range. Suchfuel oils are generally known as distillate fuel oils. It is to beunderstood, however, that this term is not restricted to straight-rundistillate fractions. The distillate fuel oils can be straight-rundistillate fuel oils, catalytically or thermally cracked (includinghydrocracked) distillate fuel oils, or mixtures of straight-rundistillate fuel oils, naphthas and the like with cracked distillatestocks.

Moreover, such fuel oils can be treated in accordance with well knowncommercial methods, such as, acid or caustic treatment, hydrogenation,solvent refining, clay treatment, etc.

' The distillate fuel oils are characterized by their relatively lowviscosities, pour points, and the like. The principal property whichcharacterizes the contemplated hydrocarbons, however, is thedistillation range. As mentioned hereinbefore, this range will liebetween about 100 F. and about 750 F. Obviously, the distillation rangeof each individual fuel oil will cover a narrower boiling range falling,nevertheless, within the above-specified limits. Likewise, each fuel oilwill boil substantially continuously throughout its distillation range.

Particularly contemplated among the fuel oils are Nos. 1, 2, and 3 fueloils used in heating and as diesel fuel oils, and the jet combustionfuels. The domestic fuel oils gen erally conform to the specificationsset forth in ASTM Specifications D396-48T. Specifications for dieselfuels are defined in ASTM Specifications D975-48T. Typical jet fuels aredefined in Military Specification MIL-F- 5624B.

The amount of the salt of citramic acid that is added to the distillatefuel oil in accordance with this invention will depend, of course, uponthe intended purpose and the particular metal salt selected, as they arenot all equivalent in their activities. Some may have to be used ingreater concentrations than others to be effective. In most cases, inwhich it is desired to obtain all of the aforesaid beneficial results,additive concentrations varying between pounds per thousand barrels ofoil and about 200 pounds per thousand barrels of oil will be employed.It may not always be desired, however, to accomplish all of theaforementioned results. In such cases, where it is desired to effectonly one or two results, lower concentrations can be used. Thus, if itis desired only to prevent rust under dynamic conditions, as in a ficialresult, will vary generally between about one pound per thousand barrelsof oil and about 200 pounds per thousand barrels of oil. Preferably, itwlil vary between about 10 and about 200 pounds per thousand barrels ofoil.

If it is desired, the fuel oil compositions can contain other additivesfor the purpose of achieving other results. Thus, for example, there canbe present foam inhibitors and ignition and burning quality improvers.Examples of such additives are silicones, dinitropropane, amyl nitrate,metal sulfonates, and the like.

In reference to the aspect of this invention relating to lubricatingoils, the additives embodied for use are effective to impart anti-rustproperties while also inhibiting emulsification and, particularly, toimpart such properties to highly refined mineral lubricating oils foruse in stream turbines. For such usage, the additive embodied herein canbe used in amounts that can vary over a rather wide range, based on theweight of the lubricating oil but, generally, in an amount of from about0.001 to ten percent and, preferably, between about 0.05 and about onepercent. If desired, other substances can be added to the lubricatingoil to impart other properties and, for example, anti-oxidants, pourpoint depressants, V.I. improvers, extreme pressure agents, etc.

Thus, the improving agents of this invention are useful for variouspetroleum fractions in concentrations ranging from about 0.001% up toabout ten percent based on the weight of the fraction with the actualconcentration used being dependent on the particular oil fraction (fueloil or lubricating oil) and the use for which the improving agent isintended.

The following specific examples are for the purpose of illustrating themineral oil compositions of this invention, and of exemplifying thespecific nature thereof. It is to be strictly understood, however, thatthis invention is not to be limited by the particular additives andmineral oils, or to the operations and manipulations described therein.Other citramic acid salts and mineral oils, as discussed hereinbefore,can be used, as those skilled in the art will readily appreciate.

The amine reactants, Primene 81R and Primene JMT, used in the specificworking examples are mixtures of pure amines. Primene 81R is a mixtureof primary amines halvmg a carbon atom of a tertiary alkyl groupattached to the amino (NH group and containing 12 to 15 carbon atoms peramine molecule. This mixture contains, by'weight, about 85 percenttertiary-dodecyl primary amine, about 10 percent tertiary-pentadecylprimary amine, and relatively small amounts, i.e., less than 5 percentof amines having less than 12 or more than 15 carbon atoms. Primene J MTis a mixture of tertiary-alkyl primary amines containing 18 to 24carbons, having a tertiary carbon atom attached to the NH group, andcontaining, by weight, about 40 percent tertiary-octadecyl primaryamine, about 30 percent tertiary-eicosyl primary amine, about 15 percenttertiary-docosyl primary amine, about 10 percent tertiary-tetracosylprimary amine, and a small amount, less than 5 percent, other amines ashigh as tertiary-triacontyl primary amine.

Example 1 A mixture of gms. (0.5 mole) of citric acid monohydrate, 200gms. (1 mole) of Primene 81R and 300 cc. of Xylene was refluxed at -150C. for six hours to form the Primene 81R citramic acid. Water collectedduring the reflux was 27 cc. The Primene 81R citramic acid was thenadded at room temperature with stirring to 6.08 gms. (0.25 mole) ofmagnesium in the form of a magnesium methylate solution. The mixture wasgradually heated to C. and was held at 150 C. for one hour. The reactionproduct was distilled at 150 C. under house vacuum to remove all thexylene. The reaction product which weighed 272 gms., theory 284 gms.,was diluted with 272 gms. of a diluent (a parafiinic oil of 100 sec. at100 F.) and filtered through Hyflo clay. The final product,

the magnesium salt of Primese 8 1R citramic acid, which contained 50%diluent oil, was clear and fluid at room temperature.

Analysisr- Estimated: Percent Mg, 1.1; percent N, 2.5. Found: PercentMg, 1.09; percent N, 2.52.

Example 2 A mixture of 105 gms. (0.5 mole) of citric acid monohydrate,200 gms. (1 mole) of Primene 81R and 150 cc. of toluene was graduallyheated to 150 C. and was held at 150 C. for 5 hours to insure thecomplete formation of the Primene 81R citramic acid. To the Primene 81Rcitramic acid was added at room temperature with stirring 79 gms. (0.25mole) of barium hydroxide octahydrate and 312 gms. of diluent oil. Themixture was gradually heated to 150 C. and was held at 156 C. until theevolution of water ceased (about 2 hours). The reaction product wasfiltered through Hyflo clay. The final product, the barium salt ofPrimene 81R citramic acid, which contained 50% diluent oil, was clearand fluid at room temperature.

Analysis.Estimated: Percent Ba, 5.4; percent N, 2.2. Found: Percent Ba,5.87; percent N, 2.19.

Example 3 A mixture of 70 gms. (Va mole) of citric acid monohydrate,133.4 gms. mole) of Primene 81R and 200 cc. of toluene was refluxed at125135 C. for 3 hours and at 150-155 C. for 3 hours to form the Primene81R citramic acid. The amount of water collected during the reflux was18 cc., theory 18 cc. To the Primene 81 R citramic acid was added atroom temperature with stirring 7.67 gms. mole) of sodium in the form ofa sodium methylate solution. The mixture was gradually heated to 150 C.and was held at 150 C. for one hour to insure the complete formation ofthe sodium salt. The sodium salt was dilute-d with 185 gms. of diluentoil and 100 cc. of benzene. To the sodium salt was added at roomtemperature with stirring 23 gms. /6 mole+4.5 gms. excess) of calciumchloride dissolved in 150 cc. of methanol. The mixture was graduallyheated to 150 C. and was held at 150 C. for 2 hours. The reactionproduct was filtered through Hyflo clay easily. The tfinal product, thecalcium salt of the Primene 81R citramic acid, which contained 50%diluent oil was clear and fluid at room temperature.

Analysis..Estimated: Percent Ca, 1.75; percent N, 2.5. Found: PercentCa, 2.12; percent N, 2.39.

Example 4 A mixture of 70 gms. /a mole) of citric acid monohydrate,133.3 gms. /s mole) of Primene 81R and 200 cc. of toluene was refluxedat 125135 C. for 4 hours and 145-150 C. for 3 hours to form the Primene81R citramic acid. The amount of water collected during the reflux was19 cc., theory 18 cc. To the Primene 81R citramic acid was added at roomtemperature with stirring 7.67 gms. /2, mole) of sodium in the form of asodium methylate solution. The mixture was gradually heated to 150 C.and was held at 150 C. for one hour to insure the complete formation ofthe sodium salt. The sodium salt was diluted with 195 gms. of diluentoil and 100 cc. of benzene. To the sodium salt was added at roomtemperature with stirring 28.4 gms. /6 mole+5.7 gms. excess) of zincchloride dissolved in 150 cc. of methanol. The mixture was graduallyheated to 150 C. and was held at 150 C. for two hours. The reactionproduct was filtered through Hyflo clay. The final product, the zincsalt of the Primene 81R citramic acid, which contained 50% diluent oil,was clear and fluid at room temperature.

Analysis-Estimated: Percent Zn, 2.5; percent N, 2.4. Found: Percent Zn,3.43; percent N, 2.34.

Example 5 A mixture of 70 gms. /3 mole) of citric acid monohydrate 133.3gms. /a mole) of Primene 81R and 200 cc.

of toluene was refluxed at -125 C. for 3 hours and at 150-159 C. for 3hours to form the Primene 81R citramic acid. Water collected during thereflux was 19 cc., theory 18 cc. The citramic acid, diluted with 370gms. of diluent oil, was then added at room temperature with stirring to8.1 gms. /s mole) of magnesium in the form of a magnesium methylatesolution. The mixture was gradually heated to 150 C. and then filteredthrough Hyflo clay. The final product, the methoxy magnesium salt ofPrimene 81R citramic acid, which contained 66 /3 diluent oil, was clearand fluid.

Analysis.-Estimated: percent Mg, 1.5; percent N, 1.7. Found: percent Mg,1.46; percent N, 1.68.

Example 6 A mixture of 70 gms. /s mole) of citramic acid monohydrate,133.3 gms. /3 mole) of Primene 81R and 200 cc. of toluene was refluxedat 115-125 C. for 2 hours and at -155 C. for 4 hours to form the Primene81R citramic acid. Water collected during the reflux was 19 cc., theory18 cc. The Primene 81R citramic acid, diluted with 412 gms. of diluentoil, was then added at room temperature with stirring to a zincmethylate solution obtained by refluxing 15.3 gms. /s mole) of sodium inthe form of a sodium methylate solution and 56.7 gms. /3 mole+11.4 gms.excess) of zinc chloride previously dissolved in 200 cc. of methanol.The mixture was gradually heated to 150 C. and was held at 150 C. forone hour. The reaction product was then filtered through Hyflo clay. Thefinal product, the methoxy zinc salt of Primene 81 R citramic acid,which contained 66 /3% diluent oil, was clear and fluid at roomtemperature.

Analysis.-Estimated: percent Zn, 3.5; percent N, 1.5. Found: percent Zn,3.98; percent N, 1.47.

Example 7 A mixture of 105 gms. (0.5 mole) of citric acid monohydrate,300 gms. (1 mole) of Primene J MT and 300 cc. of xylene was refluxed at150 C. for 6 hours to form the Primene JMT citramic acid. Watercollected was 27 cc., theory 27 cc. The Primene JMT citramic acid,diluted with 394 gms. of diluent oil, was then added at room temperaturewith stirring to 6.08 gms. (0.25 mole) of magnesium in the form ofmagnesium methylate solution. The mixture was gradually heated to C. andwas held at 150 C. for one hour. The reaction product was filteredthrough Hyflo clay and distilled to 150 C. under house vacuum to removethe xylene. The final product, the magnesium salt of Primene J MTcitramic acid, which contained 50% diluent oil, was clear and fluid.

Analysis.--Estimated: percent Mg, 0.77; percent N, 1.7. Found: percentMg, 0.8; percent N, 1.73.

Example 8 A mixture of 105 gms. (0.5 mole) of citric acid monohydrate,300 gms. (1 mole) of Primene JMT a nd 150 cc. of toluene was refluxed at125-135" C. for 3 hours and at 150-160 C. for 2 hours to form thePrimene JMT citramic acid. Water collected during the reflux was 27 cc.,theory 27 cc. To the Primene JMT citramic acid was added at roomtemperature with stirring 79 gms. (0.25 mole) of barium hydroxideoctahydrate and 412 gms. of diluent oil. The mixture was graduallyheated to 150 C. and was held at 150 C. for 2 hours. The reactionproduct was filtered through Hyflo clay. The final product, the bariumsalt of Primene JMT citramic acid, which contained 50% diluent oil, wasclear and fluid at room temperature.

Analysis.-Estimated: percent Ba, 4.1; percent N, 1.7. Found: percent Ba,4.32; percent N, 1.61.

Example 9 A mixture of 52.5 gms. (0.25 mole) of citric acid monohydrate,150 gms. (0.5 mole) of Primene JMT and 200 cc. of toluene was refluxedat 117135 C. for 2 hours and at 150-157 C. for 3 hours to form thePrimene JMT citramic acid. The amount of water collected during thereflux was 14 cc., theory 13.5 cc. The Primene JMT citramic acid,diluted with 196 gms. of diluent oil, was then added at room tempertaurewith stirring to 6.08 gms. (0.25 mole) of magnesium in the form of amagnesium methylate solution. The mixture was gradually heated to 150 C.and was held at 150 C. for one hour. The reaction product was filteredthrough Hyflo clay. The final product, the methoxy magnesium salt ofPrimene J MT citramic acid, which contained 50% diluent oil, was clearand fluid at room temperature.

Analysis.-Estimated: percent Mg, 1.5; percent N, 1.7. Found: percent Mg,1.46; percent N, 1.68.

Example 10 A mixture of 70 gms. /s mole) of citric acid monohydrate, 200gms. /3 mole) of Primene J MT and 200 cc. of toluene was refluxed at115-135 C. for 3 hours and at 145155 C. for 3 hours to form the PrimeneJ MT citramic acid. Water collected during the reflux was 19 cc., theory18 cc. The Primene JMT citramic acid, diluted with 273 gms. of diluentoil, was then added at room temperature with stirring to a zincmethylate solution obtained by refluxing 15.3 gms. /s mole) of sodium inthe form of a sodium methylate solution and 56.7 gms. /3 mole+11.4 gms.excess) of zinc chloride previously dissolved in 200 cc. of methanol.The mixture was gradually heated to 150 C. and was held at 150 C. forone hour. The reaction product was filtered through Hyflo clay. Thefinal product, the methoxy zinc salt of Primene J MT citramic acid,which contained 50% diluent oil, was clear and fluid at roomtemperature.

Analysis.Estimated: percent Zn, 3.9; percent N, 1.7. Found: percent Zn,4.36; percent N, 1.49.

Example 11 A mixture of 105 gms. (0.5 mole) of citric acid monohydrate,100 gms. (0.5 mole) of Primene 81R and 184 gms. of xylene was refluxedat 135142C. until water stopped coming over (about 3 hours) to form themono- Primene 81R citramic acid. To the mono-Primene 81R citramic acidwas added at room temperature with stirring 6.08 gms. (0.25 mole) ofmagnesium in the form of a magnesium methylate solution. The mixture wasgradually heated to 140 C. and was held there for one hour. The reactionproduct was filtered through Hyflo clay. The final product, themagnesium salt of mono-Primene 81R citramic acid, which containedapproximately 50% xylene, was fluid at room temperature.

Analysis.-Estimated: percent Mg, 1.65; percent N, 1.9. Found: percentMg, 1.7; percent N, 2.03.

Example 12 A mixture of 105 gms. (0.5 mole) of citric acid monohydrate,150 gms. (0.5 mole) of Primene JMT and 200 cc. of xylene was refluxed at135145 C. until water stopped coming over (about 3 hours) to form themono- Primene J MT citramic acid. To the mono-Primene J MT citramic acidwas added at room temperature with stirring 6.08 gms. (0.25 mole) ofmagnesium in the form of a magnesium methylate solution. The mixture wasgradually heated to 140 C. and was held there for 1 hour. The reactionproduct, diluted with 234 gms. of diluent oil, was filtered throughHyflo clay and distilled to 150 C. under house vacuum to remove all thexylene. The final product, the magnesium salt of mono-Primene JMTcitramic acid, which contained approximately 50% diluent oil was fluidat room temperature.

Analysis.Estimated: Percent Mg, 1.28; percent N, 1.49. Found: percentMg, 1.45; percent N, 1.58.

Example 13 A mixture of 105 gms. (0.5 mole) of citric acid monohydrate,100 gms. (0.5 mole) of Primene 81R and 221 gms. of xylene was heatedunder reflux until water stopped coming over (about 3 hours) to form themono-Primene 81R citramic acid. To the mono-Primene 81R citramic acidwas added at room temperature with stirring 34.35 gms. (0.25 mole) ofbarium in the form of a barium methylate solution. The mixture wasgradually heated to 135 C. and was held at 135 C. for one hour. Thereaction product was filtered through Hyflo clay. The final product, thebarium salt of mono-Primene 81R citramic acid, which containedapproximately 50% xylene, was fluid at room temperature.

Analysis.Estimated: Percent Ba, 7.8; percent N, 1.58. Found: Percent Ba,9.52; percent N, 2.01.

Example 14 A mixture of gms. (0.5 mole) of citric acid monohydrate, 150gms. (0.5 mole) of Primene J MT and 200 cc. of xylene was refluxed at-145 C. until water stopped coming over (about 3 hours) to form themono-Primene 1 MT citramic acid. To the mono-Primene J MT citramic acidwas added at room temperature with stirring 34.35 gms. (0.25 mole) ofbarium in the form of a barium methylate solution and 271 gms. ofdiluent oil. The mixture was gradually heated to 155 C. and was held at155 C. until the xylene stopped coming over. The reaction product wasfiltered through Hyflo clay. The final product, the barium salt ofmono-Primene J MT citramic acid, which contained approximately 50%diluent oil, was fluid at room temperature.

Analysis.-Estimated: Percent Ba, 6.3; percent N, 1.29. Found: PercentBa, 6.64; percent N, 1.36.

Example 15 A mixture of 105 gms. (0.5 mole) of citric acid monohydrate,gms. (0.5 mole) of Primene J MT and 200 cc. of xylene was refluxed at135-145 C. until water stopped coming over (about 3 hours) to form themono-Primene 1 MT citramic acid. To the mono-Primene J MT citramic acidwas added at room temperature with stirring 11.5 gms. (0.5 mole) ofsodium in the form of a sodium methylate solution. The mixture Wasgradually heated to 135 C. to form the sodium salt. To the sodium saltwas added at room temperature with stirring 42 gms. (0.25 mole +8 gms.excess) of Z Cl dissolved in 200 cc. of methanol. The mixture wasgradually heated to 150 C. and was held at 150 C. for 2 hours. Thereaction product was diluted with 242 gms. of diluent oil and filteredthrough Hyflo clay. The final product, the zinc salt of mono-Primene JMTcitramic acid, which contained approximately 50% diluent oil was fluidat room temperature.

Analysis.Estimated: Percent Zn, 3.3; percent N, 1.45. Found: Percent Zn,4.24; percent N, 1.53.

Example 16 A mixture of 105 gms. (0.5 mole) of citric acid monohydrate,100 gms. (0.5 mole) of Primene 81R and 200 gms. of xylene was refluxedat 135142 C. until water stopped coming over to form the mono-Primene81R citramic acid. To the mono-Primene 81R citramic acid was added atroom temperature with stirring 11.5 gms. (0.5 mole) of sodium in theform of a sodium methylate solution. The mixture was gradually heated to135 C. to form the sodium salt. To the sodium salt was added at roomtemperature with stirring 42 gms. (0.25 mole+8 gms. excess) of ZnCldissolved in 200 cc. of methanol. The mixture was gradually heated to135 C. The reaction product was filtered through Hyflo clay. The finalproduct, the zinc salt of mono-Primene 81R citramic acid, which containsapproximately 50% xylene, was fluid at room temperature.

Analysis-Estimated: Percent Zn, 4.2; percent N, 1.8. Found: Percent Zn,5.24; percent N, 1.97.

9 Example 17 A mixture of 105 gms. (0.5 mole) of citric acidmonohydrate, 150 grns. (0.5 mole) of Primene J MT and 200 cc. xylene wasrefluxed at 135-145 C. until water stopped coming over (about 3 hours)to form the mono-Primene J MT citramic acid. To the mono-Primene J MTcitramic acid was added at room temperature with stirring 11.5 grns.(0.5 mole) of Na in the form of a sodium methylate solution. The mixturewas gradually heated to 135 C. to form the sodium salt. The sodium saltwas diluted with 247 grns. of diluent oil. To the sodium salt was addedto room temperature with stirring 34.8 grns. (0.25 mole+7 gms. excess)of CaCl dissolved in 200 cc. of methanol. The mixture Was graduallyheated to 150 C. and was held at 150-155 C. for one hour. The reactionproduct was filtered through Hyflo clay. The final product, the calciumsalt of mono-Primene JMT citramic acid, which contained approximately50% diluent oil, was fluid at room temperature.

Analysis.-Estimated: Percent Ca, 2.0; percent N, 1.4. Found: Percent N,2.93; percent N, 1.86.

Example 18 A mixture of 105 grns. (0.5 mole) of citric acidmonohydrate,100 gms. (0.5 mole) of Primene 81R and 187 gms. of xylene was refluxedat 135142 C. until water stopped coming over (about 3 hours) to form themono-Primene 81R citramic acid. To the mono-Primene 81R citramic acidwas added at room temperature with stirring 11.5 grns. (0.5 mole) ofsodium in the form of a sodium methylate solution. The mixture wasgradually heated to 135 C. to form the sodium salt. To the sodium saltWas added at room temperature with stirring 34.8 grns. (0.25 mole+7 gms.excess) of CaCl dissolved in 300 cc. of methanol. The mixture wasgradually heated to 125 C. and was held at 125 C. for one hour. Thereaction product was filtered through Hyfio clay steadily. The finalproduct, which contained approximately 50% xylene, was fluid at roomtemperature.

Analysis-Estimated: percent Ca, 2.8; percent N, 1.9. Found: percent Ca,2.64; percent N, 1.53.

Example 19 A mixture of 105 grns. (0.5 mole) of citric acid monohydrate,150 gms. (0.5 mole) of Armeen S and 250 gms. of xylene was refluxed at135142 C. to form the mono- Armeen S citramic acid. To the mono-Armeen Scitramic acid was added at room temperature with stirring 6.08 grns.(0.25 mole) of magnesium in the form of a magnesium methylate solution.The mixture was gradually heated to 130 C. The reaction product, beingviscous, was diluted with 234 grns. of xylene and filtered through Hyfioclay. The final product, the magnesium salt of mono-Armeen S citramicacid, which contained approximately 66%% xylene was fluid at roomtemperature.

Analysis-Estimated: percent Mg, 0.87; percent N, 1.00. Found: percentMg, 0.83; percent N, 1.00.

Example 20 A mixture of 52.5 grns. (0.25 mole) of citric acidmonohydrate, 150 grns. (0.5 mole) of Armeen S, and 400 cc. of xylene wasrefluxed at 140 C. for about hours to form the di-Armeen S citramicacid. To the di-Armeen S citramic acid was added at room temperaturewith stirring 3.04 gms. (0.125 mole) ofmagnesium in the form of amagnesium methylate solution and 191 gms. of diluent oil. The mixturewas gradually heated to 155 C. and was held there for one hour. Thereaction product was filtered through Hyflo clay. The final product, themagnesium salt of di-Armeen S citramic acid, which contained 50% diluentoil, was fluid at room temperature.

Analysis-Estimated: percent Mg, 0.78; percent N, 1.9. Found: percent Mg,0.61; percent N, 1.93.

In the following Table I, data are set forth showing the resultsobtained by subjecting to the following screenclogging test, a base fueloil with and without the addition agents embodied herein.

Screen clogging The anti-screen clogging characteristics of a fuel oilwere determined as follows: The test is conducted using a Sundstrand V3or S1 home fuel oil burner pump with a self-contained -mesh monel metalscreen. About 0.05 percent, by weight, of naturally-formed fuel oilsediment, composed of fuel oil, water, dirt, rust, and organic sludge ismixed with 10 liters of the fuel oil. This mixture is circulated by thepump through the screen for 6 hours. Then, the sludge deposit on thescreen is washed off with normal pentane and filtered through a taredGooch crucible. After drying, the material in Gooch crucible is washedwith a 50-50 (volume) acetone-methanol mixture. The total organicsediment is obtained by evaporating the pentane and the acetone-methanolfiltrates. Drying and weighing the Gooch crucible yields the amount ofinorganic sediment. The sum of the organic and inorganic deposits on thescreen can be reported in milligrams recovered or converted into percentscreen clogging.

TABLE 1 Screen clogging tests [Inhibitors blended in a fuel oil blendcomprlsing 60% cctalytically cracked component and 40% straight runcomponent-approximately 320-640 F. boiling range] Coucn. lb. 1,000 bbls.

Screen Clogging, percent Inhibitor As is apparent from the data in TableI, the addition agents embodied herein are markedly effective forinhibiting the screen-clogging characteristics of fuel oils.

In the following Table II, data are set forth showing the resultsobtained by subjecting to the following sedimentation test, a base fueloil with and Without the addition agents embodied herein.

Sedimentation The test used to determine the sedimentationchar-acteristics of the fuel oils is the F. Storage Test. In this test.a 500-mil1iliter sample of the fuel oil under test is placed in aconvected oven maintained at 110 F. for a period of 12 weeks. Then, thesample is removed from the oven and cooled. The cooled sample isfiltered through a tared asbestos filter (Gooch crucible) to removeinsoluble matter. The Weight of such matter in milligrams is reported asthe amount of sediment. A sample of the blank, uninhibited oil is runalong with a fuel oil blend under test. The effectiveness of a fuel oilcontaining an inhibitor is determined by comparing the weight ofsediment formed in the inhibited oil With that formed in the uninhibitedoil.

1 1 TABLE II Fuel oil storage tests [Inhibitors blended in a fuel oilblend comprising 60% catalytically cracked component and 40% straightrun componentapproximately 320040 F. boiling range] Concn. 1b.] SedimentInhibitor 1,000 bbls. Mg/liter Uninhibited fuel blend Uninhibited. fuelblend pl 25 Uninhibited fuel blend 0 Uninhibited fuel blend plus Ex. 25Uninhibited fuel blend 0 Uninhibited fuel blend plus Ex. 3 50 27Uninhibited fuel blend 0 77 Uninhibited fuel blend plus Ex 4 50 61Uninhib ited fuel blen 0 77 Uninhibited fuel blend plus Ex. 5 50 17Uninhibited fuel blend 0 77 Uninhibited fuel blend plus Ex. 50 30Uninhibited fuel blend O 18 Uninhibited fuel blend plus Ex. 25 3Uninhiblted fuel blend 0 77 20 Uninhibited fuel blend plus Ex. 50Uninhibited fuel blend 0 129 Uninhibited fuel blend plus Ex. 50 56Uninhibited fuel blend 0 20 Uninhibited fuel blend plus Ex. 12. 25 2Uninhibited fuel blend 0 20 Uninhibited fuel blend plus Ex. 13. 25 3 25Uninhibited fuel blend 0 129 Uninhibited fuel blend plus Ex. 14. 50 41Uninhibitcd fucl blend 0 129 Uninhibited fuel blend plus Ex. 17. 25 70Uninhibitcd fuel blend 0 129 Uninhibited fuel blend plus Ex. 18 25 57 Asis apparent from the data in Table II, the addition agents embodiedherein inhibit the tendency of fuel oils against sedimentation onprolonged storage.

In the following Tables III and N, data are shown for, respectively, theresults of tests of (a) a fuel oil with and without the addition agentsembodied herein, and (b) a light turbine oil with and without theaddition agents embodied herein to determine the effectiveness of theaddition agents as anti-rust agents. Such tests were carried out underthe conditions of ASTM Rust Test D-665 operated at 48 hours at 80 F.using distilled water.

TABLE III ASTM Rust Test D665 [Inhibitors blended in a fuel oil blendcomprising 60% catalytically cracked component and straight runcomponcntapproximately 320-640 F. boiling range] Inhibitor Concn., RustTest p.p.m. Result Blank fuel blend 0 Fail.

Blank fuel blend plus Ex. 1.. 10 Pass.

Blank fuel blend plus Ex. 2.. 10 Do. Blank fuel blend plus Ex. 3.- 10Do. Blank fuel blend plus Ex. 4 50 Do. Blank fuel blend plus Ex. 5 10Do. Blank fuel blend plus Ex. 7 10 Do. Blank fuel blend plus Ex. 10 Do.Blank fuel blend plus Ex. 10 Do. Blank fuel blend plus Ex. 50 Do. Blankfuel blend plus Ex. 10 Do. Blank fuel blend plus Ex. 10 Do. Blank fuelblend plus Ex. 10 Do. Blank fuel blend plus Ex. 10 Do. Blank fuel blendplus Ex. 10 Do. Blank fuel blend plus Ex. 16. 10 Do. Blank fuel blendplus Ex. 17. 10 Do. Blank fuel blend plus Ex. 18 50 Do.

12 TABLE IV ASTM Rust Test D-665 [Inhibitors blended in a light turbineoil] Percent Blank light turbine oil Blank light turbine oil plus Ex.Blank light turbine oil plus Ex. Blank light turbine oil plus Ex. Blanklight turbine oil plus Ex.

999995 5 9999 NNNNbhNNOJMMN As is apparent from the data in Tables IIIand IV, the addition agents of this invention effectively inhibited thefuel oils and turbine oils against rusting.

Over and above the aforesaid improvements imparted to mineral oilcompositions by the addition agents embodied herein, such additionagents also function as inhibitors against objectionable emulsification.In that respect, the presence of the tertiary carbon atom linked to thenitrogen atom in the amide grouping of the metal salts embodied hereinis important as, when corresponding metal salts, but in which thenitrogen atom is linked to a normal aliphatic group, such salts inducesevere emulsification with water. In example, reference is made toExamples 19 and 20 showing preparation of a magnesium salt of a citramicacid derived from a normal amine (Armeen S) which is a mixture ofprimary amines comprised of approximately 10% hexadecylamine, 10%0ctodecyl-amine, 35% octadecenylamine and 45% octadecadienyl. Toillustrate the importance of a tertiary carbon atom linked to thenitrogen atom in the additives embodied herein for inhibtingemulsification, fuel oil compositions were prepared by (1) addition ofthe metal salt of Example 11 at a concentratiton of 25 lbs./ thousandbarrels of a fuel oil as used for the aforedescribed fuel oil tests and(2) addition in the same concentration in such a fuel of the metal saltof Example 19 and such fuel oil compositions were subjected to thefollowing emulsion test:

Emulsion test The procedure for the fuel oil emulsion test is asfollows: a 200 milliliter portion of the fuel to be tested and 20milliliters of distilled water are placed in a clear glass pint bottle.The bottle is tightly capped and set in an Everbach mechanical shaker ina horizontal position such that the maximum degree of agitation isafforded. The shaker is run at its maximum setting for 5 minutes. Thebottle is then removed and allowed to stand in an upright position inthe dark for 24 hours. At the end of the 24 hour settling period, theappearance of the water layer is noted. The fuel layer is siphoned off,care being taken not to disturb the oil-water interface, and isdiscarded. A fresh portion of the fuel oil being tested is then added.The described sequence of steps is repeated. If no emulsion appears inthe water layer after this sequence has been performed ten times, theoil is considered to have passed the test. On the other hand, if, afterany 24 hour settling period in the procedure, there is any degree ofemulsification in the water layer, the fuel is considered to have failedthe test. This test procedure has been found to provide emulsions ininhibited oils similar to emulsions which occur in these same oils onlyafter prolonged periods of normal handling and storage in the field on acommercial basis.

Rating scale for reporting emulsion test results Description of EmulsionClean break on the interface of oil and water. No dirt,

skin, or bubbles present.

Very slight skin at the oil-water interface that usually does not breakon tilting the bottle.

Skin at oil-water interface, heavier than #1 and usually accompaniedwith dirt and bubbles on the skin. No. evidence of any white emulsion.

First sign of white emulsion. Usually forms at the bottom and in thecenter of the bottle. It is circular in shape and approximately to 1inch in diameter.

Approximately the same amount of emulsion on the bottom of the bottle as#3. However, emulsion is also beginning to form at oil-water interfaceand extends leg to ,4 downward into the water layer. Roughly 15% ofwater layer occupied by emulsion.

Circular emulsion at bottom of bottle extends outward and upwardresembling spokes. Emulsion at the interface a little thicker than #4.

More emulsion than #5. Thin film of emulsion forming on sides of bottlesurrounding the water layer. Water is still visible looking through thesides and looking up from the bottom of the bottle.

Emulsion on bottom of water layer is almost solid. Emulsion on sides ofbottle is broken in a few spots enabling the operator to see the waterlayer.

Semi-solid emulsion with perforations or bubbles similar to a honeycomb.No water visible except that seen in the bubbles.

Same emulsion as #8 but with less bubbles. 75-90% emulsion is solid.

Almost completely solid emulsion with only a few air bubbles visible.

Completely solid emulsion (Mayonnaise type).

The results obtained from the foregoing emulsion test were as follows:

It is apparent from the foregoing that the magnesium salt ofmono-Primene 81R citramic acid (EX. 11) containing a tertiary carbonatom attached to the nitrogen atom effectively inhibited emulsification(Rating 2) whereas the corresponding magnesium salt (Ex. 19) butprepared from the normal amine (Armeen S) resulted in a composition thatemulsified severely (Rating 9).

Although the present invention has been described with preferredembodiments, it is to be understood that modifications and variationsmay be resorted to, without departing from the spirit and scope of thisinvention, as those skilled in the art will readily understand. Suchvariations and modifications are considered to be within the purview andscope of the appended claims.

What is claimed is:

1. Metal salts from the group consisting of:

0 CHz-CONHR (c) metal salts of the following formulas:

CHz-CONHR CHr-CONHR HO( 3OOOH M and no-o-ooo M CH2COO 2 CH2COOI I 2 (d)metal salts of the following formulas:

CHzCONHR CH2CO-MOR' and mixtures thereof, wherein M is a Group II metal,R is an alkyl group of from four to about thirty carbon atoms and has atertiary carbon atom attached to the nitrogen atom, and R is a saturatedaliphatic hydrocarbon group.

2. Metal salts as defined in claim 1, wherein R is a saturated aliphatichydrocarbon group of from one to eighteen carbon atoms.

3. Metal salts as defined in claim 1, wherein M is a metal from thegroup consisting of magnesium, barium, calcium and zinc.

4. Metal salts as defined in claim 1, wherein R contains 12 to 24 carbonatoms, R contains one to eighteen carbon atoms, and M is a metal fromthe group consisting of magnesium, barium, calcium and zinc.

5. Metal salts as defined in claim 1, wherein R is a 40 methyl group.

References Cited by the Examiner TOBIAS E. LEVOW, Primary Examiner.

E. C. BARTLETT, H. M. S. SNEED,

Assistant Examiners.

, UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO.3,262,955 July 26, 1966 Paul YD C. Gee et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 4, line 3, for "wlil" read will line 15, for "stream" read steamcolumn 6, line 16, for "citramic read citric column 7, line 5, for"tempertaure" read temperature column 9, line 11, for "to" read at line21 for "N first occurrence, read Ca, column 10, TABLE I in the titlethereof, line 1, for "comprlsing" read comprising same TABLE I firstcolumn, line 15 thereof, for "12" read 14 column l2, lines 38 and 39,for "octodecylamine" read octadecylamine line 42, for "inhibting" read ihibiti line 44, for "concentratiton" read concentration Signed andsealed this lst day of August 1967.

(SEAL) Attest:

EDWARD M.FLETCHER, JR EDWARD J. BRENNER Attesting Officer Commissionerof Patents

1. METAL SALTS FROM THE GROUP CONSISTING OF: (A) METAL SALTS OF THEFORLLOWING FORMULAS: